
Given the opportunity, blackberry and raspberry canes become rampant thickets. The trick is to keep them contained and controlled so that they can produce berries without conquering the garden. Besides, proper pruning promotes production. Properly maintained canes are therefore both better behaved and more productive
Berry canes are certainly not low maintenance, and should be selectively pruned a few times through the year. The type of pruning needed is determined by the type of growth that the canes exhibit in particular seasons. Spent canes or upper portions of everbearing raspberry canes that produced berries through summer and early autumn will need to be removed by the end of winter while new canes that grew through this year get trained to replace them.
Pruning and thinning of new canes should be delayed until the end of winter; but removal or pruning of spent canes can begin as soon as their fruit gets depleted. Spent canes of traditional summer bearing raspberries like ‘Willamette’, ‘Tulameen’ and ‘Canby’ can be pruned to the ground. ‘September’, ‘Heritage’, ‘Summit’, ‘Fallgold’ and other everbearing raspberry canes should be pruned only as low as their fruit was produced. Lower portions that did not produce fruit should be left to bloom and produce berries next spring.
Just like raspberry canes, new blackberry canes that grew this year do not need to be pruned until late winter. However, the canes that grew last year and are finishing berry production this year can be pruned to the ground as their last berries get taken. There is no rush for this procedure, but getting it done early makes later pruning of new canes for next year a bit easier.
Of course, every different cultivar (cultivated variety) of raspberry and blackberry behaves differently. Some finish producing and are ready to be pruned sooner than others. Their behavior is also affected by climate and environmental conditions, so that the same variety may be earlier or later in different areas, or even different parts of the same garden.
Favorite berry canes are very easy to propagate by division of superfluous new shoots during winter. Alternatively, spent canes that should be removed can be ‘layered’ instead. They simply need to be bent down and partially buried, and can be dug and separated as they develop roots.
The top few inches of cane should extend above the soil. At least a few inches of cane below the top should be buried a few inches below the surface of the soil. The length of cane between the buried portion and the base of the parent plant can remain exposed.
Layering can be done at any time of year if the layer (buried section of cane) gets watered while developing roots. Layering this time of year is easiest though, because layers get plenty of water from rain through winter, and develop roots most efficiently as they come out of dormancy late in winter or early in spring. If layers are buried where new plants are desired, they do not need to be dug and moved next year.